To limit the region exposed to the X-ray beam in X-ray examination apparatuses, absorption means are used, being arranged between the X-ray source and the X-ray detector. For example, to limit the radiation to parts of the anatomy, clinicians position shutters to delimit the region of interest. In addition to shutters completely hiding the covered region, wedges are described in U.S. Pat. No. 3,631,249. This document describes a diaphragm with plates shaped as wedges producing a half shade effect compared to a primary ray diaphragm. However, positioning of absorption means is time consuming, especially when performed manually. As a result, inaccuracy or even no use at all may reduce the image quality and may also increase the total radiation exposure dose.